The present invention relates to an automatic injection apparatus for animals, in particular chicks.
Chicks have to be vaccinated a few days after birth. The vaccination operation, which is preferred by way of injection, should be a quick one enabling in a relatively short time to vaccinate a large number of chicks, without requiring much man power and expensive apparatus.
There are known injection apparatus for this purpose, e.g., those described and claimed in U.S. Pat. Nos. 3,964,481, 4,108,176 and 4,276,879. Said devices comprise mainly a work plate on which the animal to be injected is placed, said plate being provided with an aperture through which a syringe needle may protrude to inject the animal, a syringe which is mounted on the side on which the animal is to be injected, first means for moving said syringe back and forth between a first position in which the syringe needle is entirely withdrawn and a second position in which said syringe needle protrudes through said aperture as well as means activating at the required moment said first means.
However, said known apparatus have certain drawbacks. Thus in the device of U.S. Pat. Nos. 3,964,481 and 4,276,879, as first means an electric motor is utilized. This has serious drawbacks in that such motors cause safety problems, in particular in wet hatcheries. Moreover, this apparatus although it is portable can be utilized only in the vicinity of a source of a wall current. Said electric motor is replaced in the apparatus of U.S. Pat. No. 4,108,176 by a piston (fluid motor). However, this apparatus has the drawback that said piston works in one direction only and is retracted by the force of a spring. This spring very often breaks and has then to be replaced in a rather complicated manner. Moreover, in such apparatus the syringe cannot be mounted on a support in a tight manner as this may also cause the breaking of the spring. Thus the syringe cannot be fixed on said support in a precise manner.
Moreover, most of the known apparatus have the common drawback that they are arranged in a closed housing, which can be opened only by complicated means. This brings about the replacement of parts, e.g., the above mentioned spring and/or the cleaning of the several parts becomes quite a complicated operation.